[mattbrewsbytes]

I think most of the intermediate to hard concepts, best practices, etc. are usually learned on the job as you run into problems and solve them. I would also guess that more of the advanced things tend to be on the backend. A todo list application front end built from a tutorial will likely scale for one user or thousands of concurrent users.

The other aspect of advanced is how to maintain an application and write it so its easier to maintain. Once something is live, how you get changes in, fix bugs, monitor, etc. is not really talked about online because it is boring. It is a combo of process, tooling and some tech.